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authorAndreas Schwab <schwab@linux-m68k.org>2013-01-19 22:17:45 +0100
committerAndreas Schwab <schwab@linux-m68k.org>2013-01-19 23:47:27 +0100
commit32ebef017fedc457963cf1b50f1afd28cac41080 (patch)
treeffb940a7fbcf06da75d4fabf6ec666e55bae58d2
parent41597a7c021d3f0f0ab3d6f7fb5aa92cab6a916f (diff)
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Add backtrace for m68k
-rw-r--r--ports/ChangeLog.m68k2
-rw-r--r--ports/sysdeps/m68k/backtrace.c159
2 files changed, 161 insertions, 0 deletions
diff --git a/ports/ChangeLog.m68k b/ports/ChangeLog.m68k
index ca77de8..e470ed8 100644
--- a/ports/ChangeLog.m68k
+++ b/ports/ChangeLog.m68k
@@ -1,5 +1,7 @@
2013-01-19 Andreas Schwab <schwab@linux-m68k.org>
+ * sysdeps/m68k/backtrace.c: New file.
+
* sysdeps/unix/sysv/linux/m68k/nptl/not-cancel.h: New file.
* sysdeps/unix/sysv/linux/m68k/syscalls.list: Add waitpid.
diff --git a/ports/sysdeps/m68k/backtrace.c b/ports/sysdeps/m68k/backtrace.c
new file mode 100644
index 0000000..decd03c
--- /dev/null
+++ b/ports/sysdeps/m68k/backtrace.c
@@ -0,0 +1,159 @@
+/* Return backtrace of current program state.
+ Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <bits/libc-lock.h>
+#include <dlfcn.h>
+#include <execinfo.h>
+#include <stdlib.h>
+#include <unwind.h>
+
+struct trace_arg
+{
+ void **array;
+ int cnt, size;
+ void *lastfp, *lastsp;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_Ptr (*unwind_getip) (struct _Unwind_Context *);
+static _Unwind_Ptr (*unwind_getcfa) (struct _Unwind_Context *);
+static _Unwind_Ptr (*unwind_getgr) (struct _Unwind_Context *, int);
+static void *libgcc_handle;
+
+static void
+init (void)
+{
+ libgcc_handle = __libc_dlopen ("libgcc_s.so.2");
+
+ if (libgcc_handle == NULL)
+ return;
+
+ unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
+ unwind_getip = __libc_dlsym (libgcc_handle, "_Unwind_GetIP");
+ unwind_getcfa = __libc_dlsym (libgcc_handle, "_Unwind_GetCFA");
+ unwind_getgr = __libc_dlsym (libgcc_handle, "_Unwind_GetGR");
+ if (unwind_getip == NULL || unwind_getgr == NULL || unwind_getcfa == NULL)
+ {
+ unwind_backtrace = NULL;
+ __libc_dlclose (libgcc_handle);
+ libgcc_handle = NULL;
+ }
+}
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+# define unwind_getcfa _Unwind_GetCFA
+# define unwind_getgr _Unwind_GetGR
+#endif
+
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+ struct trace_arg *arg = a;
+
+ /* We are first called with address in the __backtrace function.
+ Skip it. */
+ if (arg->cnt != -1)
+ arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+ if (++arg->cnt == arg->size)
+ return _URC_END_OF_STACK;
+
+ /* %fp is DWARF2 register 14 on M68K. */
+ arg->lastfp = (void *) unwind_getgr (ctx, 14);
+ arg->lastsp = (void *) unwind_getcfa (ctx);
+ return _URC_NO_REASON;
+}
+
+
+/* This is a global variable set at program start time. It marks the
+ highest used stack address. */
+extern void *__libc_stack_end;
+
+
+/* This is the stack layout we see with every stack frame
+ if not compiled without frame pointer.
+
+ +-----------------+ +-----------------+
+ %fp -> | %fp last frame--------> | %fp last frame--->...
+ | | | |
+ | return address | | return address |
+ +-----------------+ +-----------------+
+
+ First try as far to get as far as possible using
+ _Unwind_Backtrace which handles -fomit-frame-pointer
+ as well, but requires .eh_frame info. Then fall back to
+ walking the stack manually. */
+
+struct layout
+{
+ struct layout *fp;
+ void *ret;
+};
+
+
+int
+__backtrace (void **array, int size)
+{
+ struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+#ifdef SHARED
+ __libc_once_define (static, once);
+
+ __libc_once (once, init);
+ if (unwind_backtrace == NULL)
+ return 0;
+#endif
+
+ if (size >= 1)
+ unwind_backtrace (backtrace_helper, &arg);
+
+ if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+ --arg.cnt;
+ else if (arg.cnt < size)
+ {
+ struct layout *fp = (struct layout *) arg.lastfp;
+
+ while (arg.cnt < size)
+ {
+ /* Check for out of range. */
+ if ((void *) fp < arg.lastsp || (void *) fp > __libc_stack_end
+ || ((long) fp & 1))
+ break;
+
+ array[arg.cnt++] = fp->ret;
+ fp = fp->fp;
+ }
+ }
+ return arg.cnt != -1 ? arg.cnt : 0;
+}
+weak_alias (__backtrace, backtrace)
+libc_hidden_def (__backtrace)
+
+
+#ifdef SHARED
+/* Free all resources if necessary. */
+libc_freeres_fn (free_mem)
+{
+ unwind_backtrace = NULL;
+ if (libgcc_handle != NULL)
+ {
+ __libc_dlclose (libgcc_handle);
+ libgcc_handle = NULL;
+ }
+}
+#endif